[Objective] The farmers' legitimate rights and interests in the process of land conversion were investigated in order to provide a scientific basis to formulate a national new compensation standard. [Methods] Viewed from the philosophical concept of value, this paper constructed a comprehensive farmland value framework. Using methods of income reduction, equivalent factor and the shadow price, the comprehensive values of farmlands in Siping City of Jilin Province were quantified and evaluated. [Results] (1) The comprehensive value was evaluated as 1.33×10⁶ yuan/hm². In which, the economic value was 4.56×10⁵ yuan/hm², the ecological value was 3.74×10⁵ yuan/hm², the social value was 2.87×10⁵ yuan/hm², the development right value of farmland was 2.18×10⁵ yuan/hm². (2) The actual compensation value in land conversion was 4.50×10⁵ yuan/hm²; (3) In the process of land conversion, the loss of farmers' land rights and interests was 8.84×10⁵ yuan/hm², [Conclusion] In 2012, the actual compensation value accounted for only 33.7% of land comprehensive value. This reflected a fact that the land rights and interests of land-lost peasants were trespassed. It is considered that the limiting understanding of farmland value, the unreasonable compensation standard for land acquisition, the imperfect land expropriation regime, the fuzziness land property rights are all the main causes that the land-lost farmers' land rights and interests is treated unjustly in the process of land conversion.